textproduct: Albany

WHAT HAS CHANGED

Based on latest radar/satellite trends, have added isolated showers for this morning for areas mainly N and W of Albany, along with increased cloud coverage. Small-scale mid level shortwave amid warm advection leading to band of mid level clouds and light showers/sprinkles across central NY tracking northeast. Coverage of any showers should remain isolated and intensity light.

KEY MESSAGES

1) Widespread showers and scattered thunderstorms are expected late this afternoon through late tonight. Confidence is low in the threat for severe thunderstorms, but there is high confidence that all showers and thunderstorms will be capable of producing heavy downpours and gusty winds which could pose minor societal impacts.

2) Cooler and drier weather return to eastern New York and western New England for the beginning of the work week.

3) Additional rounds of showers and thunderstorms are expected from the middle through the end of the upcoming week. However, Thursday holds the highest probability for severe thunderstorms.

DISCUSSION

KEY MESSAGE 1...

A mid- to upper-level shortwave, rotating through the base of a closed upper low just east of the James Bay, is currently digging south and east through the Upper Midwest per latest water vapor imagery. Meanwhile, the latest SPC mesoscale analysis places a surface cyclone just to its north and east with an elongated cold front extending south and west through the central Great Lakes and down through the central Plains. Along the boundary, a surface wave looks to be in the beginning stages of closing off into a low in central Michigan with a secondary low already developed in northeastern Missouri. Throughout the day, the aforementioned shortwave will deepen along its southeast trajectory, sinking farther into the Ohio Valley before taking on a negative tilt as it enters the Mid- Atlantic by this evening. Likewise, the cold front will shift eastward as its parent low retrogrades north and westward. The lows along the cold front will begin to deepen as it gains eastward momentum, triggered by the deepening of the shortwave aloft, subsequently strengthening forcing for ascent across our region. As a result, widespread showers and potential thunderstorms will develop late this afternoon along and ahead of the cold front, lasting through late tonight when the front departs our region to the southeast.

Severe Threat...The Storm Prediction Center has maintained the Slight Risk (Level 2 of 5) across much of our CWA for today. However, there are several factors leading to low confidence in the overall threat for severe thunderstorms. The first concern is the overall lack of substantial instability. Warm conditions amid a southerly to southwesterly flow regime ahead of the front will ultimately provide at least weak instability across area today. This will be especially true given the expectation for breaks of sun this morning. However, increasing cloud coverage into the afternoon should ultimately limit the destabilization of our pre-frontal environment. Likewise, deep mixing across the entire region will also keep dewpoints within the 50s and 60s which, with highs in the upper 70s to low 90s, will also limit buoyancy.

The second concern is the timing of the front itself. Over the last 48 hours or so, the guidance has come into good agreement that the front won't actually begin its passage until late this afternoon, between 19-22z. By the time it extends across a larger portion of our CWA, we will be past peak heating and will be beginning to lose daylight. This significantly limits the window of opportunity for the use of the available instability which, as previously stated, may already be limited. There may be an opportunity ahead of the front to get a storm or two, as there does appear to be a weak, pre-frontal trough that tracks through the region a few hours earlier than what the front is expected to, but an excess of low- and even mid-level dry air may limit even resulting showers. The latest CAMs seem to favor that thought, as they are not resolving much if any convection in the early to mid afternoon hours. But, if there were to be enough instability and forcing from the pre-frontal trough to generate a storm, the greatest probability would be for areas south of Albany. Here, some forecast soundings are indicating an EML with inverted-v profiles which suggests the potential for severe wind gusts. But once again limited instability (MLCAPE generally <500 J/kg) combined with the weakness of the pre-frontal trough will likely limit storm development.

Frontal Showers and Thunderstorms...Despite the low confidence in the severe threat, there is high confidence in the widespread nature of showers directly resulting from the front late this afternoon through late tonight. Overall strong forcing and southwesterly moisture advection will not only allow rain showers to become widespread, but moderate to heavy in nature as PWATs surge to 1.2" to 1.5". That said, there is not a high likelihood of flooding due to the fast nature of the front and its resulting showers, though there could be some nuisance ponding of water in urban and poor drainage areas. Additionally, it is quite possible for there to be some embedded thunderstorms as mid- level lapse rates remain marginally steep (5.5-6.5 C/km) and the environmental shear increases. In fact, this looks to become a low CAPE/high shear (<500 J/km MLCAPE and at least 30-40 kt 0-6 km shear) environment such that there may actually be some level of organization to the showers and embedded thunderstorms. 0-6 km shear vectors oriented nearly parallel to the incoming cold front suggest some linear banding segments which could also increase the probability of gusty winds. Now, while the probability of severe wind gusts may be low late this afternoon into late tonight, steep lapse rates, high PWATs erring to precipitation loading, inverted-v profiles, increasing wind flow aloft, and fast storm motion provide confidence that any shower or thunderstorm will be capable of producing gusty winds that could pose some nuisance impacts such as isolated power outages from downed trees/wires or blown about outdoor furniture.

KEY MESSAGE 2...

Conditions quickly dry out in the wake of the front tomorrow morning with temperatures finally cooling down. Highs tomorrow will be in the 60s and 70s while lows tomorrow night fall into the 40s to low 50s. High pressure building in across the region will allow dry conditions to persist into Tuesday as temperatures moderate to near seasonal normals. Values will be in the upper 60s to upper 70s before low temperatures Tuesday night fall into the mid/upper 40s to mid 50s.

KEY MESSAGE 3...

A broad troughing pattern will then begin to set up for the middle to the end of the week, forcing additional opportunities for showers and thunderstorms. In particular, we are keeping a close eye on Thursday, which holds the next best opportunity for potential severe weather. Guidance is consistently showing agreement in a deepening surface cyclone tracking through the eastern Great Lakes beneath a mid- to upper-level shortwave. High levels of bulk shear and modest instability, particularly for areas south of Albany ahead of a cold front attending the low, certainly suggest that there could be some organized convection depending on the timing. We will continue to monitor trends closely over the coming days and provide additional details as they become available.

AVIATION /13Z SUNDAY THROUGH THURSDAY/

Through 12Z/Mon...VFR conditions prevail through about 21Z today for all terminals with increasing mid and high clouds ahead of a cold front approaching from the west. There is a low to medium chance that isolated to scattered showers and/or thunderstorms will impact the terminals between 21Z/Sun and 03Z/Mon where we maintained the PROB30 group. There is even a low chance that some of these storms can be severe (highest chance at POU, ALB and PSF) producing brief damaging wind gusts; however, given lackluster output from convective allowing models, confidence remains low to include severe wind gusts in the forecast. Then, a more organized line of moderate rain and thunderstorms will arrive from northwest to southeast between 00 and 03Z/Mon continuing overnight before exiting by 07 - 10 UTC. MVFR/IFR conditions will likely occur (especially visibility due to heavy rain) with potential for gusty winds 30-35 KT or greater as the line of rain/storms arrives.

Light and variable winds through early this morning. Then winds will strengthen from the south/southwest between 10 and 15 KT in the late morning into the early afternoon with some gusts between 25 and 30 KT, strongest at KALB/KPSF. Winds shift abruptly to the west-northwest with gusts up to 25kts as rain ends by 07 - 10 UTC as the cold front pushes through the terminals.

Outlook...

Sunday Night: High Operational Impact. Breezy. Definite SHRA...TSRA. Monday: Low Operational Impact. Breezy. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: High Operational Impact. Likely SHRA...TSRA. Wednesday Night: Moderate Operational Impact. Breezy. Chance of SHRA...TSRA. Thursday: High Operational Impact. Windy With Gusts To 31 kts. Definite SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.